<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
    .download{
        /*默认不显示*/
        display: none;
    }

    .app:hover .download{
        /*鼠标放在字体上显示二维码*/
        display: block;
    }
    .app:hover .title{
        /*鼠标放在字体上显示红色*/
        color: red;
    }

    </style>
</head>
<body>
<div class="app">
    <div class="title">下载app</div>
    <div class="download">
        <img src="../static/download.png" alt="">
    </div>
</div>

</body>
</html>